Centrifugal fan.



D. B. MINOR.

GENTRIFUGAL FAN.

APPLICATION rILnn 8EPT.18, 1911.

Pamnted Mar. 19, 1912.

W/T/VESSES W UNITED STATES PATENT OFFICE.

DANIEL B. MINOR, OF ST. PAUL, MINNESOTA, ASSIGNOR '10 L. S. HACKNEY, 'OFST. PAUL, MINNESOTA.

GENTRIFUGAL FAN.

Specification of Letters Patent.

Patented Mar. 19, 1912.

' following is a specification.

M invention relates to fans designed particularly for use withventilating apparatus and the object of the invention is to provide afan of large capacity and one which will be practically noiseless.

- hereinafter Other objects of the invention will appear from thefollowing detailed description.

The invention consists generally in various constructions andcombinations, all as described and particularly pointed out in theclaims.

In the accompanying drawings forming part of this specification, Figure1 is a sectional view through the fan casing, show-.

ing a fan with my invention applied thereto, Fig. 2 is a sectional viewtaken on a section line at right angles substantially to the sectionline of Fig. 1. V

In the drawing, 2 represents a centrally arranged intake pipecommunicating with a casing having flaring walls 3.

4 and 5 represent the heads of the fan, between which blades 6 arearranged at suitable intervals, preferably a considerable distanceapart, as indicated in Fig. 2. These blades are of substantially thesame width from end to end and are rigidly secured to the heads 4 and 5.The head 4 has a shaft 7 journaled in the bearing 8. The fan revolveswithin the casing and an annular chamber 9 is formed between the flaringwalls 3 and the blades 6 of the fan. The periphery of the head 4 liesclose to the walls 3 while the periphery of the head 5 is a considerabledistance from the walls 3, forming a chamber or space increasing inwidth from one end of the fan to the other. At the exit of the chamber 9the flaring walls unite with the walls 10 of an annular chamber 11having an exit opening 12. The angle'13 where the flaring walls 3 unitewith the walls 10 is located at such a distance from the blades 6 thatthe whirring sound incidental to centrifugal fans as usually constructedis entirely eliminated.

For the purpose of accelerating the flow of air through the chamber 9and into the chamber 11 I provide a series of blades 14- mounted on theouter portion of the head 5 and twisted slightly to present inclinedsurfaces to the a1r currents and suck the air from the chamber 9 intothe chamber 11, where a revolving movement will be i1nparted to the aircurrents, causing them to flow around the surface of the walls 10 andfinally pass out through the discharge openmg 12. These blades arepreferably provided with beveled outer ends 15 and are so disposed inthe casing that the air currents will be drawn along the flaring surfaceof the chamber 9 and'sucked into the chamber 11 without impinging thesharp angle at the intersection of the walls 3 and 10 and withoutcausing the disagreeable sound that 1s so frequently objectionable infans of this type. I have found also that the use of these blades willso accelerate the flow of the air currents from the chamber 9 into thechamber 11 and out through the discharge opening that the capacity ofthe fan will be greatly increased over those of the ordinary type of thesame size. 1

I claim as my invention 1. A centrifugal fan having a casing providedwith a central intake opening, fan

heads mounted in said casing and having fan blades between them, aseries of circumferential blades mounted on one of said fan heads andprojecting outwardly therefrom, said circumferential blades acceleratingthe flow of air through said casing and said casing having an annulardischarge chamber into which the air is directed by said blades;

2. The combination, with a casing having intake and discharge openings,of a revolving fan located therein, said fan having blades extendingparallel substantially with its axis and also having a series of bladeslying in a plane at right angles substantially to the axis of said fanand projecting outwardly beyond said blades.

3. The combination, with a casing having intake and discharge openingsand provided with flaring walls, of a fan journaled in said casing andinclosed by said flaring wall and comprising heads and blades betweensaid heads, one of said heads being contiguous to said flaring wall andthe other being disposed a considerable distance from said wall, anannular chamber being formed between said blades and said flaring wall,a

series of blades carried by said last named head and projectingoutwardly toward said flaring wall and between said outlet opening andsaid chamber and operating to accelerate the flow of the air currentsthrough said chamber toward said outlet opening.

4. The combination, with a fan casing having a central intake openingand flaring Walls and an annular chamber terminating in a dischargeopening, of a fan located within said casing at one side of said annularchamber and inclosed by said flaring walls, said fan having a series ofprimary blades, there being an annular chamber formed between saidblades and said flaring walls, and a series of secondary blades carriedby said fan and disposed between said first and second named annularchambers and operating to accelerate the currents of air through saidfan and into said first named annular chamber. V

5. The combination, with a fan casing having an air intake and dischargeopening, of a centrifugal fan mounted therein and provided with heads,and a series of plates arranged at intervals between said heads and aseries of fan blades projecting outwardly from one of said heads andpresenting inclined surfaces to the air'currents and operating toaccelerate the currents of air through said fan toward said dischargeopening.

6. The combination, with a fan casing, cone-shaped in form and havingopen ends, of a centrifugal fan journaled in said casing and providedwith heads and blades between said heads, one of said heads filling,substantially, one open end of said casing and considerable space beingprovided between the other head and the opposite end of said casing, andblades carried by said fan and projecting into said space.

7. The combination, with a fan casing having an intake opening andflaring walls and a chamber terminating in a discharge opening, of a fanlocated within said casing and having a-series of primary bladestherein, a chamber being formed between said blades and said flaringwalls and a series of secondary blades carried by said fan and disposedbetween said first and second named chambers and operating to acceleratethe currents of air through said fan and into said first named chamber.

In witness whereof, I have hereunto set .55

my hand this 13th day of September 1911. DANIEL B. MINOR. Witnesses;

ASHLEY COFFMAN, W. J. ELLIOTT.

